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1983 Honda GL650I Silver Wing Interstates (1 Red, 1 Gray)
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Discussion Starter · #1 · (Edited)
So, I've started my project to install a 1983 GL1100 Interstate Gold Wing trunk in place of the passenger seat on my 1983 GL650 Interstate Silver Wing. (Just tired of not being able to lock up my $700 worth of Arai helmet and Sena blue tooth communicator when out on rides.)

I've gathered up all the parts I should need including great condition GL1100 trunk and mounting rack plus a spare GL650 trunk that I can part out and use just the bottom, etc.

Fuel tank Tire Wheel Automotive lighting Automotive tire


Going to use the bottom of the spare GL650 trunk to serve as the base for mounting the GL1100 trunk. Also going to use a 1/2" thick piece of high-density polypropylene (HDPP) to make a cover for the bottom of the GL650 trunk to serve as a mounting point for the GL1100 trunk and it's mounting bracket. Will cut away all but the top portion of the mounting bracket, just keeping the top components onto which the detachable trunk locks and secure that to the base.

So, right now I need some sort of trim molding, either plastic or rubber, to protect the aluminum trim piece on the top of the GL650 trunk base before I secure the polypropylene lid onto it. I could just secure it to the aluminum trim but the polypropylene is slippery and I would also like some protection for the aluminum trim to keep it from being damaged by the weight of the GL1100 trunk once installed. The aluminum trim is 5/16" wide. See pic below:

Hood Luggage and bags Bag Font Motor vehicle


So, what do I use as a trim molding to cover and protect that aluminum trim before installing the polypropylene lid? And, where can I get some?

I appreciate any suggestions. (In the mean time, I'll get to work cutting out the lid.)

PS) Yes, I know using a GL1200 trunk would have been easier to mount because they are not detachable like the GL1100 trunks, but they just didn't look right on the bike. The GL1100 trunk matches the look of the bike and saddlebags much better. If this works out, I'll paint the trunk to match.

Should sit about like this when I'm done, but a bit taller with the mounting bracket under it.

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So, again, what can I use for trim molding to protect the aluminum trim?
 

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I have some thin Kydex that is probably what I'd use for this, you can heat it up with a hair dryer or heat gun and mold it into shape.
 
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I thought of split loom too but I don't think it would last and it probably wouldn't look very good.

I also don't think it would work well to attach the rack to the sheet of polypropylene and then lock the trunk onto that so the polypro (& thus the edge of the original trunk) is supporting the weight, not to mention that you are going to end up with two sets of hardware for removing the trunk. It all sounds a bit Rube Goldberg to me.

I would add some blocks of wood or sections of square tubing to the parts of the original trunk that are well supported and bolt the new trunk directly to them, with the sheet that covers the original trunk a purely cosmetic piece that is sandwiched between the trunks so that it doesn't have to support anything and weight isn't bearing on the aluminum edge. That would make it stronger, eliminate the GoldWing rack and still allow you to remove the whole assembly and easily swap on the back seat or the original trunk.

BTW: I'd recommend either painting the polypropylene or doing everything possible to keep it out of direct sunlight because the UV in sunlight can cause it to degrade and become brittle over time.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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You might find one of these profiles will fit in the groove of the aluminum trim.
I agree with Bob that you should build a supporting frame inside the Silverwing trunk base. As a bonus, it would provide a hard-to-access compartment for extra-secure storage on the bike.
 
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As you determine placement be sure to leave clearance to be able to lock the side cases. you may also consider room to remove the cases without removing the trunk.
 
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1983 Honda GL650I Silver Wing Interstates (1 Red, 1 Gray)
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Discussion Starter · #7 ·
Thanks much Randall and Bob for your great suggestions on making this trunk addition more secure.

A couple of things to show where I'm at:

First, I'm stuck with using at least the very top portion of the GL1100 trunk mounting bracket. As you can see in the following picture, the bottom of the trunk is NOT flat at all. It is recessed (different amounts in different places) specifically to fit this mounting bracket, which attaches at two forward points and locks at two rearward points. There is no way to mount this trunk on a flat surface with this strangely arched recessed bottom without cracking it.

Motor vehicle Light Automotive tire Bumper Yellow


So, what I will keep of the mounting bracket is ONLY the very top part that retains the latches and locking points as shown in the following picture.

Bicycle part Automotive lighting Bicycle accessory Automotive exterior Bicycle drivetrain part


So, that leaves me with a minimal and fairly flat section of the mounting bracket that will securely hold the trunk without cracking the ABS plastic under load. Also, I believe that I will be able to use the two flat cross bars in that section of the bracket to secure it to the top of the polypropylene lid I'm making for the GL650I trunk base.

Second, I will definitely add some support structure inside the bottom of the original GL650I trunk base to help bear the weight of the GL1100 trunk. I plan to add support members across three main places as shown in the following picture.

Motor vehicle Automotive design Automotive exterior Trunk Gas


The middle one is most important since that's the spot that the metal locking bar is located underneath the bottom of the trunk base and can support the most weight. I'll probably use wood for those supports. They will mount on the bottom of the trunk base and their upper surfaces will be level with the aluminum trim strips on the top of the trunk base. This way, there will be a considerable amount of area to absorb and support the weight of the GL1100 trunk.

I did find some suitable edge trim to protect the aluminum trim strip on the trunk base. It's mostly for automotive applications, but it is quite sturdy and can bend around corners. Best picture I have of it is below.

Tool Rectangle Font Metal Auto part


So, that's the interim report and plan for now. Will be a while before I get these parts all made. I'll make another report then.

Thanks!
 

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Having both, I am very familiar with the shape of both the GL1100 and SilverWing trunks (my SilverWing trunk is in the attic because I got fed up with the shape of its bottom).
If it was me I would probably either 1) adapt the whole rack so that I could have a back seat or 2) build something that would bolt to the bike's frame and the trunk and cover in the sides to hide it if I didn't like the way it looked.

If you are determined to keep the bottom of the original trunk I'd still recommend removing the new trunk's hardware and bolting it down solidly instead of having 2 sets of hardware under it. If it isn't flat enough make something inside the original trunk that is, then put the flat plate on that and something made to fit the bottom of the new trunk above the plate.

But I still say mounting the new one on top of half of the original is pretty makeshift.
And the polypro won't hold up to sunlight.
 

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I wouldn't trust a lid (stock or fabricated) on the Silverwing box to securely hold the Goldwing trunk. Remember, weight isn't the only concern. You need to account for wind loads, uplift, lateral acceleration, etc. I'd rigidly connect the Goldwing box through the Silverwing base to its mounting system.
 
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Remembering that the SilverWing trunk itself isn't bolted down.

For the record, Eccles' CX650E frame is basically the same as the frame of a GL650. Here's what the frame that supports its trunk looks like. I don't have to worry about room under its trunk for access to saddlebags (even if the trunk was wide enough for that to matter) and it isn't going to win any beauty contests so I wasn't concerned about closing in below the trunk but you can see how simple something like that can be. In my case I was able to bolt through the inner & outer fender, the frame cross member and the trunk so it is very solidly mounted with a light frame.
204348


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Discussion Starter · #11 ·
Thanks again Randall and Bob for the additional suggestions. I'll probably end up with some version of the methods that we've discussed so far.

A couple of things on my design feature list I should have mentioned. First off, it will definitely be a 1-up touring bike for me. After 47 years of riding on the back seat with me, my wife is no longer comfortable on the back seat of any of my remaining 2-wheelers. She will only ride with me on the back of our GL1800 Gold Wing CSC Trike. So, that's the reason I want the trunk where the passenger seat would normally be, plus at my age I really like having a backrest behind me on the rider's seat.

Also, it had been a goal to make this addition a quickly convertible option, i.e. I could quickly install or remove either the stock GL650I trunk or the GL1100 trunk assembly that I'm making. Thus the reason I wanted to retain the GL650I trunk base as a foundation. That said, if I can't get this GL1100 convertible trunk assembly constructed in a sturdy enough fashion, I'll abandon the idea and not use the GL650I trunk as a base.

I did find two pictures on the forum of someone who mounted the trunk where I want it (without using any portion of the GL650I trunk), but WITH at least the top portion of the GL1100 trunk mounting bracket with key locks. You can see that in this picture:

Light Motor vehicle Bumper Automotive design Automotive exterior


You can clearly see the top portion of the GL1100 trunk mounting bracket in place under the trunk. So some portion of the mounting bracket was used in this installation. There also seems to be two metal braces attached to the mounting bracket headed straight down and connected to some mounting point on the bike.

This second picture shows some of the mounting arrangement from the side.

Wheel Vehicle registration plate Tire Automotive lighting Fuel tank


It looks to me like the passenger seat is actually still in place on this installation. Also looks like a portion of the mounting bracket forward of the two latches toward the front of the trunk was also retained and somehow attached to the bike somewhere near the side of the passenger seat.

Wish I could find more pictures of how much of the mounting bracket was used and to what other points on the bike that it's attached to. But, these were the only two I could find.

So, lots to decide before I start cutting stuff up!
 

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It is hard to tell from those pics whether the passenger seat is in place or not. It is possible that he used most of the GL1100 rack and the trunk is farther back than it looks ion those pics. Do you have a link to the thread they are from?

As for bing able to remove the trunk, that could be a good idea but you really only need 1 way to remove it. I'd say removing the original one completely and mounting the 1100 rack to your bike's frame would probably be the best way but if you really want to mount the new one on top of the original I'd attach it solidly and remove the whole assembly when you don't want the big trunk.

BTW: The GL1100's rack (#10 below) really is more than just a mounting bracket for the trunk. Aside from the fact that when the trunk is removed it works for strapping cargo onto like any other motorcycle rack it is also part of the set that includes the combined rear crash bars and saddlebag brackets (#13 & 14).
In the day several manufacturers made trailer hitch mounts that replaced the U tube (#9), which had strap brackets that ran up to the upper rear saddlebag bolt for extra support (my GW came with one but I eventually got fed up with the extra steps every time I had the wheel out so I traded it to someone for the original tube).
Branch Organism Font Auto part Slope


I can't remember off hand whether the rack is necessary for the bag mounts but even though I rarely use the trunk since I added the sidecar I left the rack on because it is handy sometimes ;-)
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Discussion Starter · #13 ·
... if you really want to mount the new one on top of the original I'd attach it solidly and remove the whole assembly when you don't want the big trunk.
That's kind of my plan at this point. If I can't get it to work, I'll try to fit the GL1100 mounting bracket to my bike without using any part of the GL650 trunk.

Here's the thread I saw those pictures in:

 

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Have a look at the first couple of pics in post#14 of that thread and then post #17. It looks like he had the 1100 trunk bolted to a piece of plywood that replaced the top of the original trunk (quite similar to your idea but stronger). SteveinPA's profile says he visited the forum a few weeks ago so maybe it might b a good idea to ask him why he changed to mounting it on a rack behind the passenger seat (one pic shows the bike with both trunks in place).
 

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Kawazywingr has a GW trunk mounted behind the passenger seat on his GL500I. It was a dealer option when bought by my friend Charlie's brother. I wonder if it's the same mounting as the above example.
 
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Discussion Starter · #16 ·
Have a look at the first couple of pics in post#14 of that thread and then post #17. It looks like he had the 1100 trunk bolted to a piece of plywood that replaced the top of the original trunk (quite similar to your idea but stronger). SteveinPA's profile says he visited the forum a few weeks ago so maybe it might b a good idea to ask him why he changed to mounting it on a rack behind the passenger seat (one pic shows the bike with both trunks in place).
I did see those posts, which is where I got the idea for using the bottom of the GL650 trunk as the base for the install so it was convertible. Decided I didn't want plywood because it doesn't do so well getting wet, and found the thick piece of polypropylene to use instead, plus it looks better. I guess I'll find out how well it does once I start to try to attach things to it.

Think I'll PM SteveinPA and ask him just exactly how he attached the trunk to the plywood in his install.
 

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I'd trust painted plywood in the wet more than I would polypro in sunlight.
I worked in a rope & cord factory for several decades and was involved in some of the testing. You know that "good yellow nylon rope from the hardware store" that people sometimes refer to? It is neither good nor nylon, being made of polypropylene, which is the cheapest material ropes are commonly made of. We used to sell really cheap boat ropes made of it to the marinas in bulk so that they could include "free" ropes with the boats they sold, knowing that the customers would be back for new ropes in a year or 2 because of how quickly it degraded.
It was also known for the colours fading. One of our suppliers made a claim that their colours would last longer so I was given the job of preparing some samples of various colours of rope made of their material and the other supplier's and hang them outside in a sunny place for a few months. Their colours didn't fade as much but the polypro itself still started to fall apart just as fast.
 
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